The reproductive system facilitates sexual maturation of individuals and sexual reproduction of offspring.
In the male, this includes the production of semen and its delivery to the outside environment.
Specific anatomical adaptations, such as the penis, facilitate semen delivery close to the site of conception, within the female reproductive tract.
Semen comprises sperm cells and seminal plasma, which nourishes and protects the sperm.
Reproductive structures are classified as either primary or accessory (aka, secondary):
The primary structures are referred to as gonads; their function is to produce gametes, aka, sex cells. In males, the primary structures are the testes (aka, testicles), which produce sperm and hormones.
The accessory structures are the organs, ducts, and glands that facilitate delivery of the gametes to the external environment.
Ejaculation
Emission is when semen is ushered into proximal urethra.
Expulsion is when semen is projected through urethra.
Continuous with epididymis, ascends to enter the pelvis, then passes over the urinary bladder and ureter.
It is a muscular tube that actively conducts sperm from the epididymis to the ejaculatory duct; this transport occurs during the emission phase of ejaculation.
Ampulla is the widened end of the ductus deferens.
Contributes the majority of the total seminal plasma volume.
Ejaculatory duct
Drains the ductus deferens and the seminal vesicle into the prostatic urethra.
Prostate gland
Its secretions enter the prostatic urethra.
Bulbourethral glands (aka, Cowper's glands)
Lie lateral to the prostate and secrete lubricating mucus into the spongy urethra.
During the expulsion phase of ejaculation, secretions from the bulbourethral glands precede the rest of the seminal fluid.
Clinical correlations:
Vasectomy: the paired ductus deferens are surgically sealed shut; sperm is still produced, but cannot be transported to the ejaculatory ducts to join the seminal plasma.
Thus, it is a highly effective form of contraception that is sometimes surgically reversed.
Cryptorchidism, aka, undescended testis, is a common birth abnormality in boys; the testicles usually move into the scrotum on their own, but, if not, surgery may be necessary.
Complications of cryptorchidism include increased likelihood of testicular cancer and reduced fertility.